Example #1
0
  /** @return ability mean */
  public double abilityMean() {
    double mean = 0;
    for (Examinee examinee : objects) {
      mean += examinee.getAbility();
    }

    return mean / objects.size();
  }
Example #2
0
  /**
   * @return variance of sample of examinees
   * @throws Exception
   */
  public double abilityVariance() throws Exception {
    if (objects.size() == 1) return 0;

    double mean = abilityMean();
    double var = 0;
    for (Examinee examinee : objects) {
      double square = examinee.getAbility() - mean;
      var += square * square;
    }
    return var / (objects.size() - 1);
  }
Example #3
0
 @Override
 public int getId(Examinee object) {
   // TODO Auto-generated method stub
   return object.getId();
 }